Hybrid Nickel Ferrite Nanotubes Doped Polyaniline Nanocomposite and Its Dielectric Properties

Abstract

Nanotubes of nickel ferrite were prepared by the citrate method and were used in nanocomposite synthesis via in situ polymerization technique. The structural and surface morphology characterizations were carried out by Fourier-transform infrared spectroscopy (FTIR), x-ray powder diffraction (XRD), and scanning electron microscopy (SEM) techniques. FTIR spectra show the characteristic peaks of benzenoid ring, quinoid ring, and nickel ferrite stretching of tetrahedral and octahedral sites. XRD pattern shows the cubic spinal structure of NiFe₂O₄ nanotubes and it remaining undistorted even after dispersion in a polyaniline matrix. The SEM image of 15 wt.% nanocomposite shows that the polyaniline coated nickel ferrite nanotubes form a length about 100 nm. Furthermore, the DC conductivity shows three steps conductivity feature and among all prepared nanocomposites, the 15 wt.% shows high conductivity of 1.89 S/cm. This is due to high absorption at activation energy of 0.213 × 10⁻² J/mol and elongation of nanocomposites chain length which is confirmed from the negative thermal coefficient (NTC) graph. The vibrating sample magnetometer (VSM) study shows the saturation magnetization decrease after formation of polyaniline nanocomposite. The dielectric properties were analyzed by impedance analyzer, and it was found that 15 wt.% nanocomposite shows the lowest dielectric constant and dielectric loss as a result of high ac conductivity of about 1.32 S/cm which is due to the sharp drop in bulk resistance and low relaxation time of 0.1375 μs as evidenced from the cole-cole plot.